I think 8mm rifles will share the same fate as the .303 once the surplus supply of Yugo 8mm runs out (get it while you can!).

8mm at least has a very large and dedicated cult following and there are umpteen million 8mm Mauser rifles of various types out there. New 8mm ammo is still manufactured en masse in Europe and it not uncommon among small manufacturers in the US, either. I think they will remain popular for quite a long time, with or without surplus. For me, the appeal of dirt cheap corrosive ammo is offset by the lower accuracy and the extra cleaning effort required when you can get full power S&B loads that are very nice and far less expensive than domestic caliber hunting rounds.

I have a small reserve of 8mm Norma and Nosler hunting rounds for sighting and harvesting only.